Vacuum-actuated screen.



No. 896,473. PATBNTED AUG. 18,1908.`

H. G. SHORTT.

VACUUM -AGTUATED SCREEN. MPL'IOATION FILED 13.80.19, 1907.

4 SHEETS-SHEET 1.

No. 896,473. PATENTED AUG. 18, 1908.VA`

H. G. 'SH0RTT- VACUUM AGTUATBD SCREEN.

AAPPLICATION FILED DBO.19, 1907.

4 SHEETS-SHEET 2.

N0. 896,473. PATENTBD AUG. 1s, 1908.`

H. G. SHORTT.

VACUUM AGTUATED SCREEN.

APPLICATION FILED DBO.19 1907.

l .4 SHEETS-SHEET 4 UNITED sTATEs PATENT oEEIcE.

IIOWARD G. SHORTT, OF GARTHAGE, NEW YORK, ASSIGNOR OF ONE-THIRD TO JOHN G. JONES AND ONE-THIRD TO EDWARD G. SHORTT, OF GARTHAGE, NEW YORK.

VACUUM-ACTUATED SCREEN.

Specification of Letters Patent.

Patented Aug. 18, 1908.

Application filed December 19, 1907. Serial No. 407 ,207.

To all whom it may concern:

Be it known that I, HOWARD G. SHOETT, a citizen of the United States, residing at Carthage, in the county of Jeerson and State of New York, have invented certain new and useful Improvements in Vacuum- Actuated Screens; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the letters and iigures of reference marked thereon, which form a part of this z specification.

rhis invention relates to new and useful improvements in screens for treating wood pulp or other material and consists in the rovision of means whereby a vacuum of force may be applied to operate a diaphragm, thereby imparting a quick upstroke to the screen resulting in the freeing of the slots in the plates of stock or any foreign matter which may become lodged therein. Heretofore `it has been the practice in screens for this purpose to connect the diaphragm direct with a cam, whereas by the apparatus involved in my invention the operation of the apparatus may be greatly accelerated, thereby greatly increasing the capacity of the The invention comprises various details of construction and combinations and arrangements of parts which will be hereinafter fully described and then specifically defined in the appended claims.

My invention is illustrated in the accompanying drawings, in which Figure 1 is a vertical sectional View through the screen. Fig. 2 is a vertical sectional view showing the piston at its extreme lower end of stroke. Fig. 3 is a vertical sectional view through the pneumatic piston on its'upstroke. Fig. 4 is an enlarged sectional view of the relief Valve showing a modiiication in which a spring is added to the valve, if desired. Fig. 5 is a top plan sectional View taken on line A-A of Fig. 1, showing the stock outlet ports from the top of the diahraOm. Fig. 6 is a vertical sectional view' on line B-B of Fig. 5. Fig. 7 is a side elevation, partly in section showing the diaphragm at its up position.

Reference now being had to the details .of the drawings by letter, A designates a standard upon which the screen box B is mounted, having a suitable screen C mounted therein and C designates a pipe through which the stock is fed into the box and upon said screen.

D designates a diaphragm which is mounted within a screen box below the screen, there being two of said diaphragms, one upon either side of the transverse center of the box as illustrated in Fig. 5 of the drawings and intermediate the diaphragms are formed the ports E leading into the delivery box E, shown clearly in Figs. 1, 5 and 6 of the drawings. Fixed to eachdiaphragm is a plate D2 having a stem D3 projecting from the face thereof, said stem being mounted in a guideway D4 positioned centrally in the openin D5 which is formed in the casting F secured to the bottom ofthe screen box, as clearly illustrated in Figs. 1 and 7 of the drawings. Said casting F has securely fastened thereto a pneumatic cylinder G in which a power piston I-I is adapted to have a reciprocating movement and H is a pitman connected to a pin h upon the piston I-I and its other end to a strap H2 mounted upon the eccentric I which is keyed to the driving shaft I/ It will be noted that there are two eccentrics connected to separate pistons, one for operating the diaphragm, only one, however, of the pneumatic cylinders being illustrated in Fig. 1 of the drawings, although a portion of the second piston and eccentric are illustrated in elevation in said figure.

A coiled spring J is mounted about the stem D3 and the guide D, in which said stem reciprocates, and one end of the spring bears against the plate D2 upon the diaphragm and its other end against a portion of the casting D5 in which said stem is mounted, the purpose of said spring being to return the diaphragm to its normal position after having been drawn downward by a suction force, due to the formation of a vacuum in the cylinder G and the passageway leading therefrom to the under side of the diaphragm. Said cylinder G has ports g formed therein to allow air to enter the cylinder to break the vacuum and allow the diaphragm to be returned to its normal position by the action of the spring bearing against the same. A relief port K leads from the upper portion of said cylinder to a valve regulated port N in which a valve N is mounted, thereby allowing the air above the piston II to make exit to the atmosphere and avoid any unnecessary compression Cfr of the air in the cylinder or passageway leading therefrom to the space below the diaphragm. If, however, compression is desired to perform the duties of said spring J, a spring L, shown in Fig. 4 of the drawings, may be utilized, which spring L is placed about the stem of the valve N, thus retaining the pressure within the cylinder G equal to the weight or strength of said spring L Mounted within the flow boX M is a dam M over which, when the screen stock rises to the stock level upon the diaphragm, will run over into the discharge opening Q, shown in Figs. 5 and 6 of the drawings, and from which it may be conveyed to any suitable location.

In operation, the stock being fed through the screen boX runs through the slots in the screen and, at each rotary movement of the driving shaft l, a diaphragm is drawn down as illustrated in Fig. 1 by a suction force due to the formation of a vacuum within the cylinder as the piston moves outward. When the piston H reaches the position shown in Fig. 2 of the drawings so as to open the ports g in the wall thereof, air rushing into the portion of the cylinder above the piston will cause the vacuum formed therein to be broken and the diaphragm will move quickly upward, thereby clearing the slots of the screen of any stock or foreign matter which may become lodged therein. Upon the return upper or inner throw of the piston H, when the latter closes the ports g and assuming the position shown in Fig. 3 of the drawings, any air which may be trapped in the space above the piston will make exit through the relief port K and the valve-regulated duct N to the atmosphere to avoid compression of the air in the cylinder and space leading therefrom to the diaphragm. Upon the neXt outer throw of the piston, the same operation is repeated. The screen stock passing through the port E into the iiow boX will seek its level in the screen boX and run into the flow boX M and run over the dam at the end thereof to the discharge opening from which it may be conveyed to any suitable location.

By the provision of an apparatus as shown and described, it will be understood that a series of rapid strokes may be imparted to the pistons, causing quick vibratory movements to be imparted to the diaphragm whereby any foreign matter lodging in the slots of the screen may be freed therefrom and, as the diaphragms are entirely separate from the pistons, it will be impossible to break the screen plates by their becoming plugged as is commonly a trouble in screens having direct connection with cam actuated mechanism. Vhen the diaphragm has direct connection with a cam eccentric actuated mechanism, the vacuum created above the diaphragm, it has been found, will invariably collapse the screen plate. In the event of any leakage through the diaphragm, the

water will pass through the casting, from which it will be expelled through the relief ports by the reciprocating movement of the piston in said cylinder.

What I claim to be new is 1. A pulp screening apparatus comprising a stock receptacle with the screen therein, a diaphragm mounted beneath the screen, a

pneumatic cylinder having a free communi-v cating space intermediate the same and said diaphragm, a piston mounted within said cylinder and adapted to form a vacuum Within the cylinder to move the diaphragm in one direction, and means for returning the diaphragm to its normal position independent of the action of the piston, as set forth.

2. A pulp screening apparatus comprising a frame, a stock receptacle, a screen mounted therein, a diaphragm mounted beneath said screen, an apertured pneumatic cylinder communicating with the space underneath said diaphragm, and a power piston mounted in said cylinder, and affording means whereby an unbalanced atmospheric pressure may be brought to bear upon the diaphragm to vibrate the same, as set forth.

3. A pulp screening apparatus comprising a frame, a stock receptacle with a screen therein, a diaphragm mounted within said receptacle, a spring bearing against the diaphragm, an apertured pneumatic cylinder communicating with the space below the diaphragm, a power piston mounted in said cylinder, and means for reciprocating said cylinder and adapted to cause an unbalanced atmospheric pressure to vibrate the diaphragm, as set forth.

4. A pulp screening apparatus comprising a frame, a stock receptacle with a screentherein, a diaphragm mounted in said receptacle, an apertured pneumatic cylinder communicating with the space underneath said diaphragm, a spring bearing yieldingly against the diaphragm, a power piston in said cylinder, an eccentric actuated pitman connected to said piston, as set forth.

5. A pulp screening apparatus comprising a frame, a stock receptacle with a screen therein, a diaphragm mounted in said receptacle, an apertured pneumatic cylinder communicating with the space underneath said diaphragm, a spring bearing yieldingly against the diaphragm, a power piston in said cylinder, an eccentric actuated pitman connected to said piston, and a valve regulated relief port communicating between said cylinder and the atmosphere, as set forth.

6. A pulp screening apparatus comprising a stock receptacle, a screen therein, a diaphragm in said receptacle, an apertured cylinder communicating with the space underneath the diaphragm, apower iston mounted in said cylinder and indepen ent ofthe diaphragm, and means for reciprocating said piston, as set forth.

7. A pulp screening apparatus comprising a stock receptacle with a screen therein, a diaphragm mounted in said receptacle, an apertured pneumatic cylinder with a passageway leading into the space underneath said diaphragm, a spring mounted within said space, and bearing yieldingly against the diaphragm, a power piston in said cylinder, an eccentric operated pitman connected with said piston, and a valve regulated relief port leading from the cylinder to the diaphragm, as set forth.

S. A pulp screening apparatus comprising a stock receptacle, a screen therein, with a delivery box having ports communicating between the same and said receptacle, a iiow box communicating with said delivery box, a screen plate in the receptacle a diaphragm, a spring bearing yieldingly against the diaphragm, an apertured pneumatic cylinder communicating with the space under the said diaphragm, a power piston in said cylinder, an eccentric Operated pitman connected to said piston, as set forth.

9. A pulp screening apparatus comprising a stock receptacle with a screen therein, a diaphragm mounted within the receptacle, a hollow casting fitted to the screen receptacle, a spring mounted in said casting and bearing yieldingly against the diaphragm, an apertured pneumatic cylinder fastened to said casting and communicating therewith, a power piston in said cylinder, a driving shaft, an eccentric thereon, a pitman actuated by said eccentric and pivotally connected to said piston, as set forth.

10. A pulp screening apparatus comprising a stock receptacle with a screen plate therein, a diaphragm in the receptacle, a plate secured to said diaphragm, a boss projecting from said plate, a spring mounted about said boss and bearing against said plate, an apertured pneumatic cylinder communicated with the space immediately below said diaphragm, a valve regulated relief port communicating between said cylinder and the atmosphere, a power piston mounted in said cylinder, and means for operating the latter, as set forth.

11. A pulp screening apparatus comprising a stock receptacle with suitable delivery and flow boxes, a screen in said receptacle, a diaphragm, a plate secured to said diaphragm, a boss projecting from said plate, a hollow casting fixed to said receptacle, a shell mounted in said casting, and in which said boss has a reciprocating movement, a spring about said boss, and shell, and bearing against said diaphragm, an apertured pneumatic cylinder communicating, with the space immediately below the diaphragm, through said casting, a valve regulated relief port communicating between the said cylinder and the atmosphere, a power piston in said cylinder, and means for operating the same, as set forth.

In testimony whereof I hereunto affix my signature in the presence of two witnesses.

HOWARD G. sHORTT.v

Witnesses:

JOHN G. JONES, FRED M. WING. 

